Valve stem guide



Aug. 30, 1938. 5, HEWEL 2,128,414

VALVE STEM GUIDE Filed March 28, 1936 INVENTOR F Q/7MB Hewefi ATTORNEY WITNESS Patented Aug. 30, 1938 UNITED STATES PATENT OFFICE 10 Claims.

My invention relates to valve stem guides for the valve stems of internal combustion engines and the like.

One object of my invention is to provide a valve stem guide which will prevent sticking of the valve stems during operation thereof in the engine, either by reason of expansion caused by heating of the parts or by friction or by reason of the suction of oil along the valve stem and the consequent formation of gummy substances.

A more specific object of my invention is to provide a valve stem guide having a structure so designed as to completely prevent all causes of sticking of the valve stems by so treating the upper and lower ends and the central portion of my valve stem guide in diiferent manners as to overcome their respective tendencies to stick for different reasons.

Other objects of my invention will become evident from the following detailed description taken in conjunction with the accompanying drawing, in which:

Figure 1 is a view in longitudinal section, taken through a portion of an internal combustion engine, embodying my present invention;

Fig. 2 is an enlarged view in side elevation of my improved valve stem guide or sleeve;

Fig. 3 is a View in longitudinal section, taken along the line IIIIII of Fig. 2;

Figs. 4 and 6 are, respectively, a top plan and a bottom plan view of the structure shown in Fig. 2; and

Fig. 5 is a transverse section, taken along the line VV of Fig. 2. 7

Referring to the drawing, the structure here shown comprises a section of an internal combustion engine I, including a cylinder 2, a reciprocatory piston 3 therein, the usual spark plug 4 at the head of the cylinder, a cam shaft 5 of a usual character for reciprocating a valve stem 6, on the upper end of which a valve 1 is provided for controlling the ingress of combustible gas to the cylinder 2, and my improved valve stem guide 8, which is located in the usual position in the engine block near the cylinder 2 for properly guiding the valve stem 6 in its reciprocatory movements.

Referring more particularly to Figs. 2 to 6, in elusive, my improved valve stem guide, which is preferably a unitary body composed of some suitable ferrous material, comprises an upper section II, a middle section or body l2 and a lower section l3, all of which are treated in different manners, as hereinafter more fully described, to prevent sticking of the respective portions of my valve stem guide on the valve stem during its operation.

The valve stem guide 8 may be of any preferred form, being shown here as tapering upwardly from the bottom portion I3 through the middle or bottom portion l2, while the upper portion H is of reduced diameter.

A suitable opening or bore I4 extends from the top of my valve stem guide through the portions H and I2 and into the lowerportion l3 where it communicates with an enlarged counterbore 19 at the lower end of the guide, so that a certain annular space surrounds the valve stem 6 Where encased by the lower portion I3 of my valve stem guide. The purpose of this counter- 15 bore or enlarged opening l9 will be hereinafter pointed out in detail.

The upper section II and also, if desired, the lower section l3 are provided with a plurality, here shown as four, of slots or cuts l5 which are filled with bronze inserts I6 brazed in place and smoothed off, whereby, by reason of the different coefficients of heat expansion of the ferrous material comprising the remainder of the valve stem guide and of the bronze inserts, the corresponding portions H and I3 of the valve stem guide do not stick to the valve stem during operation thereof by reason of the expansion of the bronze inserts.

The central or body portion of the valve stem guide is provided with a relieved part comprising a plurality of internal circumferential grooves ll surrounding the bore l4, thereby providing a series of alternating grooves I1 and ribs or bearing surfaces l8. Consequently, when the central 3 portion of my valve stem guide is under high compression, by reason of the expansion of the surrounding portion of the engine block as a result of high heating thereof, the pressure exerted on the valve stem by the central portion of my valve stem guide is reduced by reason of the provision of these alternate grooves and ribs. Thus, for the central portion of my valve stem guide, the tendency to stick is removed as a result of this reduction in pressure exerted on the valve stem.

The purpose of the large counterbore l9 at the lower end of the lower portion l3 of my valve stem guide is to break the vacuum or suction action that would otherwise occur along the valve stem if a tight fit obtained between it and the lower portion l3. Consequently, the outer lower section or wall of the portion l3, in the first place, acts as a shield or skirt to prevent the oil spray from actually hitting the enclosed portion of the valve stem, and secondly, there is thus practically no oil on that enclosed portion of the valve stem to be sucked therealong into the bore I4 during the reciprocatory movements of the valve stem.

As a result of this absence of oil along the valve stem inside of the bore l4, there is no tendency in my construction to create carbon and gum on the valve stem to cause it to stick.

It will be seen that I have thus provided a valve stem guide which embodies three different means, namely, the bronze inserts IE3 at the top, the alternating grooves ll and ribs H8 in the middle section and the enlarged counterbore I9 at the bottom, for so treating the respective sections of the valve stem guide as to prevent their particular j tendency to cause the valve stem to stick therein,

As a result, my valve stem guide, as a whole,

serves to prevent sticking of; the valve stem therein from any cause, thereby making for improved operation of the internal combustion enginein I which my valve stem guides are incorporated and longer life of the valve stem and valve stem guide.

I do not wish to be restricted to thespe'cific structural details or arrangement of parts herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed thereon as are indicated in the appended claims.

I claim as my invention:

1. A valve stem guide for preventing a recip rocatoryj valve stem from sticking therein comprising a portion having metals of different .00- efiicients of heat expansion for jointly contacting the valve stem and expanding away therefrom, a second portion having an internal relieved part to reduce pressure on the valve stem, and another portion counterbored to prevent oil suction along the reciprocatory stem. v

2. A valve stem guide for preventing a reciprocatory valve stem from sticking'therein comprising metals of different coefficients of heat expansion for jointly contacting the valve stem and expanding away therefrom, internal pressure-reducing means and oil-suction-prevention means.

3. A valve stem guide for preventing a reciprocatory valve stem from sticking therein comprising an end portion having inserts of a different coefiicient of heat expansion, 'an internally grooved central portion to reduce pressure on the valve stem, and another end portion with an enlarged opening surrounding the valve stem to prevent oil suction therealong during its reciprocatory motion. a i

4. A valve stem guide for preventing a reciprocatory valve stem from sticking therein comprising an end portion having longitudinal slots filled with inserts of a different coefiicient of heat expansion, a central portion having spaced con.- tact with the valve stem to reduce pressure thereon, and another end portion with a counterbore materially larger in diameter than the valve stem to prevent oil suction therealong during its reciprocatory movements.

5. A valve stem guide of ferrous metal for preventing a reciprocatory valve stem from sticking therein comprising an upper end portion having longitudinal 'slots filled with bronze, a central portion having a plurality of spaced internal ribs for contacting the valve stem to reduce pressure vthereon, and a lower end portion with a counterbore materially larger in diameter than the valve stem to prevent suction of oil into the central portion-of the guide as the valve stem is reciprocated therein.

6. A valve stem guide for preventing a reciprocatory valve stemfrom sticking therein comprising an end portion having inserts of a different coefficient of heat expansion for jointly contacting the valve stem and expanding away therefrom, said inserts extending to the edge of said end portion.

7. A valve stem guide for preventing a reciprocatory valve stem from sticking therein comprising an end portion having longitudinal slots extending to the edge of said end portion filled with inserts of a different coefficient of heat expansion for jointly contacting the valve stem and expanding away therefrom, said inserts extending to the edge of said end portion. I

8. A valve stem guide of ferrous metal fo.rprew venting a reciprocatory valve stem from sticking therein comprising an end portion having longitudinal slots extending to the edge of said end portion filled with bronze inserts for jointly conta'cting the valve stem and expanding away therefrom, said inserts extending to the edge of said end portion.

v 9. A valve stem guide for preventing'a smooth reciprocatory valve stem from sticking therein comprising an internally grooved central portion to reduce pressure on the valve stem, said central portion directly abutting both end portions of said guide to form a unitary body.

10. A valve stem guide for preventing a smooth reciprocatory valve stem from sticking therein comprising a central portion having a plurality of spaced internal ribs for contacting the valve stem to reduce pressure thereon, said central portion directly abutting both end portions of said guide to form a unitary body.

FRANK B. I-IEIWEL. 

